require 'digest/sha1'
class User < ActiveRecord::Base
    # Virtual attribute for the unencrypted password
    attr_accessor :password

    validates_presence_of     :login, :email
    validates_presence_of     :password,                   :if => :password_required?
    validates_presence_of     :password_confirmation,      :if => :password_required?
    validates_length_of       :password, :within => 4..40, :if => :password_required?
    validates_confirmation_of :password,                   :if => :password_required?
    validates_length_of       :login,    :within => 3..40
    validates_length_of       :email,    :within => 3..100
    validates_uniqueness_of   :login, :email, :case_sensitive => false
    before_save :encrypt_password
    
    has_many :users_urls
    has_one :profile
    # Authenticates a user by their login name and unencrypted password.  Returns the user or nil.
    def self.authenticate(login, password)
        u = find_by_login(login) # need to get the salt
        u && u.authenticated?(password) ? u : nil
    end

    # Encrypts some data with the salt.
    def self.encrypt(password, salt)
        Digest::SHA1.hexdigest("--#{salt}--#{password}--")
    end

    # Encrypts the password with the user salt
    def encrypt(password)
        self.class.encrypt(password, salt)
    end

    def authenticated?(password)
        crypted_password == encrypt(password)
    end

    def remember_token?
        remember_token_expires_at && Time.now.utc < remember_token_expires_at 
    end

    # These create and unset the fields required for remembering users between browser closes
    def remember_me
        self.remember_token_expires_at = 2.weeks.from_now.utc
        self.remember_token            = encrypt("#{email}--#{remember_token_expires_at}")
        save(false)
    end

    def forget_me
        self.remember_token_expires_at = nil
        self.remember_token            = nil
        save(false)
    end

    protected
    # before filter 
    def encrypt_password
        return if password.blank?
        self.salt = Digest::SHA1.hexdigest("--#{Time.now.to_s}--#{login}--") if new_record?
        self.crypted_password = encrypt(password)
    end
    
    def password_required?
        crypted_password.blank? || !password.blank?
    end
end
